**Six people have been killed by a suicide bomber at a security checkpoint in north-west Pakistan, police said.**At least 16 people were wounded by the explosion in Mingora, capital of Swat Valley.
It comes a day after twin suicide bomb attacks in the eastern city of Lahore killed 45 people and injured about 100.
The attacks follow threats by Taliban militants to send out thousands of suicide bombers if the army did not stop its offensive against them.
The Pakistani army launched a major offensive in Swat last year after peace agreements with local militants collapsed.
The area has been largely peaceful since then.
Friday’s bombings in Lahore targeted military vehicles as they drove through a crowded area.
On Monday, Taliban militants destroyed a building used by intelligence services in Lahore, killing 13 people.
In the last six months, hundreds of civilians have been killed in militant attacks across the country.